EP1098912B1 - Inhibiting scale in vinyl monomer polymerization - Google Patents

Inhibiting scale in vinyl monomer polymerization Download PDF

Info

Publication number
EP1098912B1
EP1098912B1 EP99936832A EP99936832A EP1098912B1 EP 1098912 B1 EP1098912 B1 EP 1098912B1 EP 99936832 A EP99936832 A EP 99936832A EP 99936832 A EP99936832 A EP 99936832A EP 1098912 B1 EP1098912 B1 EP 1098912B1
Authority
EP
European Patent Office
Prior art keywords
aromatic compound
terpolymer
thiourea
moles
general formula
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP99936832A
Other languages
German (de)
French (fr)
Other versions
EP1098912A1 (en
Inventor
Ramesh Krishnamurti
Sandor M. Nagy
Qi Wang
Hibib Hichri
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Oxy Vinyls LP
Original Assignee
Oxy Vinyls LP
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Oxy Vinyls LP filed Critical Oxy Vinyls LP
Publication of EP1098912A1 publication Critical patent/EP1098912A1/en
Application granted granted Critical
Publication of EP1098912B1 publication Critical patent/EP1098912B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L61/00—Compositions of condensation polymers of aldehydes or ketones; Compositions of derivatives of such polymers
    • C08L61/20—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen
    • C08L61/22—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes with acyclic or carbocyclic compounds
    • C08L61/24—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes with acyclic or carbocyclic compounds with urea or thiourea
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/002—Scale prevention in a polymerisation reactor or its auxiliary parts
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/002—Scale prevention in a polymerisation reactor or its auxiliary parts
    • C08F2/004—Scale prevention in a polymerisation reactor or its auxiliary parts by a prior coating on the reactor walls
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G14/00—Condensation polymers of aldehydes or ketones with two or more other monomers covered by at least two of the groups C08G8/00 - C08G12/00
    • C08G14/02—Condensation polymers of aldehydes or ketones with two or more other monomers covered by at least two of the groups C08G8/00 - C08G12/00 of aldehydes
    • C08G14/04—Condensation polymers of aldehydes or ketones with two or more other monomers covered by at least two of the groups C08G8/00 - C08G12/00 of aldehydes with phenols
    • C08G14/06—Condensation polymers of aldehydes or ketones with two or more other monomers covered by at least two of the groups C08G8/00 - C08G12/00 of aldehydes with phenols and monomers containing hydrogen attached to nitrogen
    • C08G14/08—Ureas; Thioureas
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L61/00—Compositions of condensation polymers of aldehydes or ketones; Compositions of derivatives of such polymers
    • C08L61/34—Condensation polymers of aldehydes or ketones with monomers covered by at least two of the groups C08L61/04, C08L61/18 and C08L61/20

Definitions

  • This invention relates to a method of inhibiting the formation of scale on surfaces that are in contact with polymerizing vinyl monomers.
  • EP 343,706 teaches that polythioureas of the general formula [NHRNHC(S)]n (where R is an arylene group substituted by a carboxylic acid group) can be used to reduce scale formation in vinyl chloride polymerization reactors.
  • JP 01,217,016 discloses a scale preventing compound comprising an alkali metal xanthogenate, polyethyleneimine, and a dialdehyde.
  • patent 4,431,783 discloses that naphthol/formaldehyde condensates formed by a base-catalyzed process are effective scale-preventing agents vinyl chloride polymerization reactors. While many of these scale prevention agents are effective in preventing scale, they can alter the color of the resulting PVC, giving it a yellowish tinge. Customers of high quality PVC prefer a pure white or colorless PVC and regard any color in the PVC as an indication of inferior quality.
  • a method of inhibiting the formation of scale on a reactor surface in contact with a polymerizing vinyl monomer comprising contacting said monomer with a terpolymer which comprises the condensation reaction product of
  • a solution of said terpolymer is prepared in a solvent and said solution is applied to reactor surfaces that are exposed to said monomer.
  • said solvent is water containing NaOH, KOH, LiOH, or Ca(OH) 2 .
  • said monomer is polymerized in an aqueous suspension or an aqueous emulsion and said terpolymer is added to said aqueous suspension or said aqueous emulsion.
  • said aromatic compound is selected from the group consisting of where Z is O or NOH, each R 1 is independently selected from OH, R, SO 3 R, and CO 2 R, and each R 2 is independently selected from R 1 , SH, SR, haloalkyl from C 1 to C 15 , alkoxyaryl, naphthyl, and polycyclic aryl from C 6 to C 15 .
  • said carbonyl compound is selected from the group consisting of compounds having the general formula where eachR 2 independently selected from R 1 , SH, SR, haloalkyl from C 1 to C 15 , alkoxyaryl, naphthyl, and polycyclic aryl from C 6 to C 15 , R 1 is OH, R, SO 3 R, or CO 2 R, and n is an integer from 1 to 10.
  • each R 2 is independently selected from R 1 , SH, SR, NH 2 haloalkyl from C 1 to C 15 , alkoxyaryl, naphthyl, and polycyclic aryl from C 6 to C 15 , and R 1 is OH, R, SO 3 R, or CO 2 R.
  • a vinyl polymerization composition containing about 0.0001 to about 0.01 wt% of a terpolymer of the type described above.
  • a vinyl polymerization reactor having a coating containing a terpolymer on its inside surfaces.
  • the terpolymer is present as a solution in a solvent of about 0.001 to about 20 wt% of the terpolymer and the aromatic compound is selected from the group consisting of compounds having the general formula and wherein about 0.1 to about 5 moles per mole of said aromatic compound of a carbonyl compound selected from the group consisting of compounds having the general formula where n is an integer from 1 to 10; and wherein about 0.1 to about 5 moles per mole of said aromatic compound of a thiourea having the general formula where Z is O or NOH, each R 1 is independently selected from OH, R, SO 3 R, and CO 2 R, each R 2 is independently selected from R 1 , SH, SR, NH 2 , haloalkyl from C 1 to C 15 , alkoxyaryl, naphthyl, and polycyclic aryl from C 6 to C 15 , and R is hydrogen, alkyl from C 1 to C 15 , or aryl, alkaryl, or
  • said solvent is water.
  • the terpolymer is about 0.0001 to about 0.01 wt% of the monomer
  • the aromatic compound is selected from the group consisting of compounds having the general formula and wherein there is about 0.1 to about 5 moles per mole of said aromatic compound of a carbonyl compound selected from compounds having the general formula where n is an integer from 1 to 10; and (C) about 0.1 to about 5 moles per mole of said aromatic compound of a thiourea having the general formula where Z is O or NOH
  • each R 1 is independently selected from OH, R, SO 3 R, and CO 2 R
  • each R 2 is independently selected from R 1 , SH, SR, NH 2 haloalkyl from C 1 to C 15 , alkoxyaryl, naphthyl, and polycyclic aryl from C 6 to C 15
  • R is hydrogen, alkyl from C 1 to C 15 , or aryl, alkaryl, or aralkyl from C 6 to C 15 .
  • said solvent is an aqueous sodium hydroxide.
  • the aromatic compound is 2'- hydroxy propiophenone or 1-naphthol.
  • said carbonyl compound is formaldehyde or an oligomer thereof.
  • thiourea is thiourea or thiosemicarbazide.
  • said aromatic compound is 2'-hydroxypropiophenone and said carbonyl compound is trioxane.
  • said aromatic compound is 1-naphthol and said carbonyl compound is formaldehyde.
  • a scale prevention agent for use in the polymerization of VCM and other vinyl monomers has been found that is very effective in preventing the formation of scale on reactor components that come in contact with the VCM. Because there is little or no scale, there are fewer fish eyes.
  • the scale prevention agent of this invention is a terpolymer of an aromatic compound, a carbonyl compound, and a thiourea derivative. It is easily prepared from commercially available, inexpensive, non-toxic materials and can be applied in an aqueous medium, thereby avoiding the use of potentially harmful and flammable organic solvents. Quite unexpectedly, the scale preventing agent of this invention does not impart any color to the resulting PVC.
  • the terpolymer used in the process of this invention is the condensation reaction product of an aromatic compound, a carbonyl compound, and a thiourea.
  • the aromatic compound contains the group: where Q is OR or SR and R is hydrogen, alkyl from C 1 to C 15 , or aryl, alkaryl, or aralkyl from C 6 to C 15 .
  • the Q group is preferably OR and the R group is preferably hydrogen as phenols are more readily available and work well.
  • Preferred aromatic compounds include: where Z is O or NOH, each R 1 is independently selected from OH, R, SO 3 R, and CO 2 R, and each R 2 is independently selected from R 1 , SH, SR, haloalkyl from C 1 to C 15 , and alkoxyaryl, naphthyl, and polycyclic aryl from C 6 to C 15 .
  • aromatic compounds examples include salicylic acid, 1-naphthol, thiosalicylic acid, hydroxybenzenesulfonic acid isomers, 4-hydroxybenzoic acid, 2'-hydroxypropiophenone oxime, and 2'-hydroxypropiophenone; 2'-hydroxypropiophenone and 1-naphthol are preferred due to their low cost, low toxicity, and good performance in the terpolymer condensate. Mixtures of the aromatic compounds can also be used.
  • the carbonyl compound can be an aliphatic mono or dialdehyde, an aromatic aldehyde, or an aliphatic mono or diketone.
  • Compounds, such as trioxane, that form the carbonyl compound under the reaction conditions are also contemplated.
  • Preferred carbonyl compounds have the general formula: where each R 2 is independently selected from the hereinabove definition and n is an integer from 1 to 10.
  • Suitable carbonyl compounds include acetaldehyde, glyoxal, benzaldehyde, dialkyl ketones such as acetone and methyl ethyl ketone, diaryl ketones such as benzophenone and ring-hydroxylated and sulfonated benzophenones, alkyl aryl ketones such as acetophenone, ring-hydroxylated acetophenones, and ring-sulfonated acetophenones, and formaldehyde and oligomers thereof, such as trioxane.
  • the carbonyl compound is formaldehyde or an oligomer thereof as those compounds have low cost, high reactivity, and are readily available.
  • the thiourea has the general formula where each R 2 is independently selected from NH 2 and the hereinabove definition hereinabove defined.
  • suitable thioureas include thiourea, thiocarbamide, monomethyl thiourea, 1,3-dimethyl-2-thiourea, 1-phenyl-2-thiourea, semicarbazide, thiosemicarbazide, and thiocarbohydrazide.
  • the preferred thioureas are thiourea and thiosemicarbazide because they work the best, are inexpensive, and are readily available. Mixtures of thioureas can also be used.
  • the terpolymer is made by preparing a mixture of its three components. For every mole of the aromatic compound, about 0.1 to about 10 moles of the carbonyl compound and about 0.1 to about 10 moles of the thiourea can be used. If less than 0.1 moles of the carbonyl compound is used, the terpolymers produced will have a lower molecular weight than desired, and if more than 10 moles of the carbonyl compound is used, the terpolymer will have low solubility. If less than 0.1 moles of the thiourea is used, the terpolymer will be less effective in preventing scale formation and, if more than 10 moles of the thiourea is used, the terpolymer will be less soluble. Preferably, for each mole of the aromatic compound, about 0.1 to about 5 moles of the carbonyl compound and about 0.1 to about 5 moles of the thiourea are used.
  • the condensation reaction of the terpolymer components is carried out in an acidic medium which also acts as the catalyst.
  • Mineral acids such as hydrochloric acid and sulfuric acid, and organic acids, such as acetic acid, can be used.
  • the strength of the mineral acid can vary in the range of about 1M to about 6M. Typically, about 50 to about 500 wt% of a catalyst is used, based on the total weight of the terpolymer components.
  • the condensation reaction of the terpolymer components can be performed in water or polar organic solvent such as an alcohol (e.g., methanol, ethanol, propanol), a ketone (e.g., acetone, methyl ethyl ketone), an ester (e.g., ethyl acetate), or a dipolar aprotic solvent, such as sulfolane, tetrahydrofuran, N,N-dimethylformamide, N-methylpyrrolidone, cyclohexanone, dimethoxyethane, or diethyleneglycol dimethyl ether.
  • Water is the preferred solvent because it is nonflammable and is not hazardous to the operator.
  • Mixed solvent systems comprising combinations of solvents, including combinations of organic solvents with water, can also be used. It is preferable to choose a solvent system such that the terpolymer product, once it is formed, is insoluble in the solution and precipitates.
  • the preparation of the terpolymer is described in the Indian Journal of Chemistry, Vol 22A, pages 117 to 119, (1983), herein incorporated by reference.
  • the aromatic compound, the carbonyl compound, and the thiourea taken together constitute from about 5 to about 50 wt% of the reaction system weight.
  • the reaction can be effected by heating to temperatures of up to 150°C for up to 8 hours.
  • Various other components can be mixed with the terpolymer to enhance its performance as an anti-fouling agent.
  • about 10 to about 500 wt% of an inorganic binder can be included as part of the scale prevention composition to increase the binding of the terpolymer to the reactor surfaces.
  • suitable inorganic binders include colloidal silica and alumina, titanium. (IV) oxide, zirconium (IV) oxide, aluminum hydroxide, vanadium (V) oxide, and sodium silicate.
  • the preferred inorganic binder is colloidal silica because of its low cost and good performance.
  • a surface active agent can also be included as part of the scale prevention composition to increase its adhesion to the reactor surfaces.
  • suitable surface active agents include poly(vinyl acetate) (PVA) of varying degrees of hydrolysis, hydroxyethyl cellulose, hydroxypropyl cellulose, phytic acid, poly(vinyl formal), and gelatin.
  • PVA poly(vinyl acetate)
  • the preferred surface active agent is PVA of varying degrees of hydrolysis because of its low cost and good performance.
  • the scale prevention composition is prepared by mixing a solution of the terpolymer, surface active agent, and the inorganic binder. If the scale prevention composition is to be applied to the surfaces of the reactor, a solvent is included, forming a solution of about 0.001 to about 20 wt% solids. Solutions of less solids are less effective and solutions of more solids inhibit the polymerization of the VCM. Preferably, the solution contains about 0.01 to about 5 wt% solids. Solvents that can be used to form the coating solution include, for example, water, alkaline water, and various organic solvents such as methylene chloride, tetrahydrofuran, dimethyl formamide, dimethylsulfoxide, and alcohols such as methanol and ethanol.
  • the preferred solvent is a caustic solution of, for example, about 10 wt% or less sodium hydroxide, as it has been found to work well; other inorganic bases such as KOH, LiOH, and Ca(OH) 2 are also expected io work well.
  • the terpolymer can be applied to the reactor walls and to reactor components that are in contact with the VCM by any suitable means including, for example, spraying, flooding, painting, and brushing. After the application, it is not necessary to evaporate the solvent from the coating composition.
  • the solids content of the coating on the reactor walls and components should be about 1 x 10 -5 to about 1 x 10 -3 g/square inch (about 1.6x10 -6 to about 1.6x10 -4 g/cm 2 ) as less may not be effective and more is unnecessary.
  • the terpolymer can also be added directly to the polymerization composition:
  • the polymerization composition typically consists of water, vinyl monomer, a free radical initiator, and an emulsifier.
  • the polymerization composition typically consists of water, vinyl monomer, a free radical initiator, and a suspending agent.
  • about 0.0001 to about 0.01 wt% of the terpolymer is added to the polymerization composition, based on the weight of the monomer. Less terpolymer is ineffective and more terpolymer may inhibit polymerization of the monomer.
  • the terpolymer of this invention can also be used in gas phase or bulk polymerizations of vinyl monomers. But the present invention is particularly suitable for polymerizations in an aqueous medium, such as suspension or emulsion polymerization.
  • the terpolymer can be used in both continuous and batch polymerizations.
  • a 1-naphthol/formaldehyde condensate was prepared as described in Example 1 of U.S. Patent 4,431,783.
  • the product was a deep blue aqueous sodium hydroxide solution of the condensate.
  • a rectangular SS-304 mill finish coupon 12.5 inches (32 cm) long, 3 inches (8 cm) wide, and 0.015 inches (0.4 mm) thick (available from Metal Samples Inc., Munford, Alabama) was rolled into a cylinder of about 3 inches (7.6 cm) long and about 3.6 inches (9 cm) in diameter, such that it would fit snugly along the walls of a 1-liter Monel autoclave.
  • a coating candidate was dissolved in 3 wt% aqueous NaOH solutions to prepare 2 wt% solutions of the scale prevention agents. These solutions were applied manually on both sides of the coupon with a brush and were allowed to dry overnight under ambient air.
  • the initiator 0.7 mL of 75 wt% tert-butylperoxyneodecanoate in odorless mineral spirits, sold as "Luperox 10M-75" by Elf Atochem N.A., was injected via a septum and the mixture was agitated at about 500 rpm. The reaction mixture was heated at a uniform rate over about 45 min. until the internal reactor temperature reached 62°C. After stirring for 5 hours, the heat was turned off, the excess vinyl chloride was vented off, and the PVC water slurry was filtered. The PVC obtained was air dried at room temperature to a constant weight.
  • a 1% poly(vinyl alcohol) 80% hydrolyzed; Aldrich
  • the autoclave was then evacuated again briefly without being stirred and cooled to about 5°C. Vinyl chloride gas was condensed into the autoclave with stirring until 1 ⁇ 4 lb (113 g) of monomer had been transferred.
  • the polymerization initiator (0.15 mL of 75 wt% "Luperox 10M-75") was syringed out and injected into the autoclave via a septum, and the mixture was agitated at 500 rpm.
  • the coolant fluid circulation to the reactor jacket was stopped and another circulating bath pre-heated to about 72°C was connected to the reactor jacket.
  • the reactor temperature was set to 62°C on the control tower.
  • Vinyl chloride polymerization was carried out using the general procedure outlined in Example 25, but no scale prevention agent was used.
  • Vinyl chloride polymerizations were carried out according to the general procedure outlined in Example 25 and many of the scale prevention agents described in the Examples. In some experiments, two or more coatings were applied on different sections of the reactor wall.
  • Vinyl chloride polymerization was carried out using the general procedure outlined in Example 25 and the scale prevention agent described in Example 22.
  • Tables 3 and 4 give the results of the vinyl chloride polymerizations of Examples 26 to 42. All reactor coatings were formulated in an 80/20 misture of 2 wt% aqueous NaOH/ethanol unless otherwise indicated. Polymerization Example Coating Example(s) Fouling Observations Solution Interfacial 26 No Coating High High 27 2 Medium High 11 Medium High 28 3 Low Medium 4 Low Medium 2 Low Medium 5 Low Medium 29 6 Low Medium 7 Low Medium 8 Low Medium 2 Low High 30 9 Medium Medium 31 15 None None 15 None Very Low 32 15 Low None 15 Very Low None 33 15 None None 34 15 Medium Low Tables 3 and 4 show that the terpolymers of this invention are as effective as commercial products in preventing scale and in yield, but produce PVC that is lighter and less yellow.
  • the word “comprise” or “comprises” means “includes or consists of” and “comprising” means “including or consisting of”.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Polymerisation Methods In General (AREA)
  • Cosmetics (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Phenolic Resins Or Amino Resins (AREA)

Abstract

Disclosed is a method of inhibiting the formation of scale on reactor surfaces in contact with a polymerizing vinyl monomer comprising contacting said monomer with a terpolymer which comprises the condensation reaction product of (A) an aromatic compound that contains the group where Q is OR or SR and R is hydrogen, alkyl from C1 to C15, or aryl, alkaryl, or aralkyl from C6 to C15: (B) about 0.1 to about 10 moles of a carbonyl compound per mole of said aromatic compound; and (C) about 0.1 to about 10 moles of a thiourea per mole of said aromatic compound.

Description

This invention relates to a method of inhibiting the formation of scale on surfaces that are in contact with polymerizing vinyl monomers.
When vinyl monomers are polymerized, scales of the polymer adhere to the reactor walls and to reactor components, such as stirrers. The deposition of this scale reduces the yield of the polymer, reduces heat transfer efficiency during heating and cooling of the reactor, and lowers monomer efficiency and general process control. Some of the scale flakes off during polymerization of the monomer and mixes with the rest of the polymer, which makes the polymer less processable and reduces its quality. For example, when vinyl chloride monomer (VCM) is polymerized, scales of polyvinyl chloride (PVC) can flake off and form "fish eyes" in the PVC.
Cleaning the reactor to remove this scale is normally required after each batch, resulting in considerable reactor downtime as well as increased cost in producing the polymer. Because VCM can become entrapped in the scale, the physical removal of the scale by an operator could result in the exposure of the operator to the harmful monomer.
EP 343,706 teaches that polythioureas of the general formula [NHRNHC(S)]n (where R is an arylene group substituted by a carboxylic acid group) can be used to reduce scale formation in vinyl chloride polymerization reactors. JP 01,217,016 discloses a scale preventing compound comprising an alkali metal xanthogenate, polyethyleneimine, and a dialdehyde. In JP 59,32,482, dithiocarboxylic acids or salts containing OC(=S)S or NC(=S)S groups and/or (RO)2P(S)SR derivatives are disclosed as scale preventing agents. U.S. patent 4,431,783 discloses that naphthol/formaldehyde condensates formed by a base-catalyzed process are effective scale-preventing agents vinyl chloride polymerization reactors. While many of these scale prevention agents are effective in preventing scale, they can alter the color of the resulting PVC, giving it a yellowish tinge. Customers of high quality PVC prefer a pure white or colorless PVC and regard any color in the PVC as an indication of inferior quality.
According to one aspect of the present invention there is provided a method of inhibiting the formation of scale on a reactor surface in contact with a polymerizing vinyl monomer comprising contacting said monomer with a terpolymer which comprises the condensation reaction product of
  • (A) an aromatic compound that contains the group
    Figure 00020001
       where Q is OR or SR and R is hydrogen, alkyl from C1 to C15, or aryl, alkaryl, or aralkyl from C6 to C15;
  • (B) about 0.1 to about 10 moles of a carbonyl compound per mole of said aromatic compound; and
  • (C) about 0.1 to about 10 moles of a thiourea per mole of said aromatic compound.
    • Preferably a solution of said terpolymer is prepared in a solvent and said solution is applied to reactor surfaces that are exposed to said monomer.
    Advantageously said solvent is water containing NaOH, KOH, LiOH, or Ca(OH)2.
    Conveniently said monomer is polymerized in an aqueous suspension or an aqueous emulsion and said terpolymer is added to said aqueous suspension or said aqueous emulsion.
    Preferably said aromatic compound is selected from the group consisting of
    Figure 00030001
    Figure 00030002
       where Z is O or NOH, each R1 is independently selected from OH, R, SO3R, and CO2R, and each R2 is independently selected from R1, SH, SR, haloalkyl from C1 to C15, alkoxyaryl, naphthyl, and polycyclic aryl from C6 to C15.
    Conveniently said carbonyl compound is selected from the group consisting of compounds having the general formula
    Figure 00040001
    where eachR2independently selected from R1, SH, SR, haloalkyl from C1 to C15, alkoxyaryl, naphthyl, and polycyclic aryl from C6 to C15, R1 is OH, R, SO3R, or CO2R, and n is an integer from 1 to 10.
    Advantageously said thiourea has the general formula
    Figure 00040002
       where each R2 is independently selected from R1, SH, SR, NH2 haloalkyl from C1 to C15, alkoxyaryl, naphthyl, and polycyclic aryl from C6 to C15, and R1 is OH, R, SO3R, or CO2R.
    According to a preferred embodiment of the present invention there is provided a vinyl polymerization composition containing about 0.0001 to about 0.01 wt% of a terpolymer of the type described above.
    According to an alternative embodiment of the present invention there is provided a vinyl polymerization reactor having a coating containing a terpolymer on its inside surfaces.
    In a preferred embodiment of the invention the terpolymer is present as a solution in a solvent of about 0.001 to about 20 wt% of the terpolymer and the aromatic compound is selected from the group consisting of compounds having the general formula
    Figure 00050001
    Figure 00050002
    and wherein about 0.1 to about 5 moles per mole of said aromatic compound of a carbonyl compound selected from the group consisting of compounds having the general formula
    Figure 00060001
       where n is an integer from 1 to 10; and wherein
       about 0.1 to about 5 moles per mole of said aromatic compound of a thiourea having the general formula
    Figure 00060002
       where Z is O or NOH, each R1 is independently selected from OH, R, SO3R, and CO2R, each R2 is independently selected from R1, SH, SR, NH2, haloalkyl from C1 to C15, alkoxyaryl, naphthyl, and polycyclic aryl from C6 to C15, and R is hydrogen, alkyl from C1 to C15, or aryl, alkaryl, or aralkyl from C6 to C15.
    Preferably said solvent is water.
    In another preferred method of the present invention the terpolymer is about 0.0001 to about 0.01 wt% of the monomer, and the aromatic compound is selected from the group consisting of compounds having the general formula
    Figure 00070001
    Figure 00070002
       and wherein there is about 0.1 to about 5 moles per mole of said aromatic compound of a carbonyl compound selected from compounds
       having the general formula
    Figure 00080001
       where n is an integer from 1 to 10; and
    (C) about 0.1 to about 5 moles per mole of said aromatic compound of a thiourea having the general formula
    Figure 00080002
       where Z is O or NOH, each R1 is independently selected from OH, R, SO3R, and CO2R, each R2 is independently selected from R1, SH, SR, NH2 haloalkyl from C1 to C15, alkoxyaryl, naphthyl, and polycyclic aryl from C6 to C15, and R is hydrogen, alkyl from C1 to C15, or aryl, alkaryl, or aralkyl from C6 to C15.
    Preferably said solvent is an aqueous sodium hydroxide.
    Advantageously the aromatic compound is 2'- hydroxy propiophenone or 1-naphthol.
    Conveniently said carbonyl compound is formaldehyde or an oligomer thereof.
    Preferably said thiourea is thiourea or thiosemicarbazide.
    According to an alternative embodiment of the present invention there is provided a terpolymer comprising the reaction product of
  • (A) an aromatic compound that contains a benzene ring substituted with the group OR or SR, or a naphthalene ring substituted with the group OR, OH, SH or SR, where R is hydrogen, alkyl from C1 to C15, or aryl, alkaryl, or aralkyl from C6 to C1;
  • (B) about 0.1 to about 10 moles of a carbonyl compound per mole of said aromatic compound; and
  • (C) about 0.1 to about 10 moles of thiosemicarbazide per mole of said aromatic compound.
    • Preferably said aromatic compound is 2'-hydroxypropiophenone and said carbonyl compound is trioxane.
    Advantageously said aromatic compound is 1-naphthol and said carbonyl compound is formaldehyde.
    A scale prevention agent for use in the polymerization of VCM and other vinyl monomers has been found that is very effective in preventing the formation of scale on reactor components that come in contact with the VCM. Because there is little or no scale, there are fewer fish eyes.
    The scale prevention agent of this invention is a terpolymer of an aromatic compound, a carbonyl compound, and a thiourea derivative. It is easily prepared from commercially available, inexpensive, non-toxic materials and can be applied in an aqueous medium, thereby avoiding the use of potentially harmful and flammable organic solvents. Quite unexpectedly, the scale preventing agent of this invention does not impart any color to the resulting PVC.
    The terpolymer used in the process of this invention is the condensation reaction product of an aromatic compound, a carbonyl compound, and a thiourea. The aromatic compound contains the group:
    Figure 00100001
    where Q is OR or SR and R is hydrogen, alkyl from C1 to C15, or aryl, alkaryl, or aralkyl from C6 to C15. The Q group is preferably OR and the R group is preferably hydrogen as phenols are more readily available and work well. Preferred aromatic compounds include:
    Figure 00110001
    Figure 00110002
    where Z is O or NOH, each R1 is independently selected from OH, R, SO3R, and CO2R, and each R2 is independently selected from R1, SH, SR, haloalkyl from C1 to C15, and alkoxyaryl, naphthyl, and polycyclic aryl from C6 to C15. Examples of suitable aromatic compounds include salicylic acid, 1-naphthol, thiosalicylic acid, hydroxybenzenesulfonic acid isomers, 4-hydroxybenzoic acid, 2'-hydroxypropiophenone oxime, and 2'-hydroxypropiophenone; 2'-hydroxypropiophenone and 1-naphthol are preferred due to their low cost, low toxicity, and good performance in the terpolymer condensate. Mixtures of the aromatic compounds can also be used.
    The carbonyl compound can be an aliphatic mono or dialdehyde, an aromatic aldehyde, or an aliphatic mono or diketone. Compounds, such as trioxane, that form the carbonyl compound under the reaction conditions are also contemplated. Preferred carbonyl compounds have the general formula:
    Figure 00120001
    where each R2 is independently selected from the hereinabove definition and n is an integer from 1 to 10. Examples of suitable carbonyl compounds include acetaldehyde, glyoxal, benzaldehyde, dialkyl ketones such as acetone and methyl ethyl ketone, diaryl ketones such as benzophenone and ring-hydroxylated and sulfonated benzophenones, alkyl aryl ketones such as acetophenone, ring-hydroxylated acetophenones, and ring-sulfonated acetophenones, and formaldehyde and oligomers thereof, such as trioxane. Preferably, the carbonyl compound is formaldehyde or an oligomer thereof as those compounds have low cost, high reactivity, and are readily available. Mixtures of carbonyl compounds are also contemplated. The thiourea has the general formula
    Figure 00120002
    where each R2 is independently selected from NH2 and the hereinabove definition hereinabove defined. Examples of suitable thioureas include thiourea, thiocarbamide, monomethyl thiourea, 1,3-dimethyl-2-thiourea, 1-phenyl-2-thiourea, semicarbazide, thiosemicarbazide, and thiocarbohydrazide. The preferred thioureas are thiourea and thiosemicarbazide because they work the best, are inexpensive, and are readily available. Mixtures of thioureas can also be used.
    The terpolymer is made by preparing a mixture of its three components. For every mole of the aromatic compound, about 0.1 to about 10 moles of the carbonyl compound and about 0.1 to about 10 moles of the thiourea can be used. If less than 0.1 moles of the carbonyl compound is used, the terpolymers produced will have a lower molecular weight than desired, and if more than 10 moles of the carbonyl compound is used, the terpolymer will have low solubility. If less than 0.1 moles of the thiourea is used, the terpolymer will be less effective in preventing scale formation and, if more than 10 moles of the thiourea is used, the terpolymer will be less soluble. Preferably, for each mole of the aromatic compound, about 0.1 to about 5 moles of the carbonyl compound and about 0.1 to about 5 moles of the thiourea are used.
    The condensation reaction of the terpolymer components is carried out in an acidic medium which also acts as the catalyst. Mineral acids, such as hydrochloric acid and sulfuric acid, and organic acids, such as acetic acid, can be used. The strength of the mineral acid can vary in the range of about 1M to about 6M. Typically, about 50 to about 500 wt% of a catalyst is used, based on the total weight of the terpolymer components.
    The condensation reaction of the terpolymer components can be performed in water or polar organic solvent such as an alcohol (e.g., methanol, ethanol, propanol), a ketone (e.g., acetone, methyl ethyl ketone), an ester (e.g., ethyl acetate), or a dipolar aprotic solvent, such as sulfolane, tetrahydrofuran, N,N-dimethylformamide, N-methylpyrrolidone, cyclohexanone, dimethoxyethane, or diethyleneglycol dimethyl ether. Water is the preferred solvent because it is nonflammable and is not hazardous to the operator. Mixed solvent systems comprising combinations of solvents, including combinations of organic solvents with water, can also be used. It is preferable to choose a solvent system such that the terpolymer product, once it is formed, is insoluble in the solution and precipitates.
    The preparation of the terpolymer is described in the Indian Journal of Chemistry, Vol 22A, pages 117 to 119, (1983), herein incorporated by reference. Typically, the aromatic compound, the carbonyl compound, and the thiourea taken together constitute from about 5 to about 50 wt% of the reaction system weight. The reaction can be effected by heating to temperatures of up to 150°C for up to 8 hours. Once the terpolymer has been prepared, it can be collected and purified if desired.
    Various other components can be mixed with the terpolymer to enhance its performance as an anti-fouling agent. For example, about 10 to about 500 wt% of an inorganic binder can be included as part of the scale prevention composition to increase the binding of the terpolymer to the reactor surfaces. Examples of suitable inorganic binders include colloidal silica and alumina, titanium. (IV) oxide, zirconium (IV) oxide, aluminum hydroxide, vanadium (V) oxide, and sodium silicate. The preferred inorganic binder is colloidal silica because of its low cost and good performance.
    About 1 to about 100 wt% are a surface active agent can also be included as part of the scale prevention composition to increase its adhesion to the reactor surfaces. Examples of suitable surface active agents include poly(vinyl acetate) (PVA) of varying degrees of hydrolysis, hydroxyethyl cellulose, hydroxypropyl cellulose, phytic acid, poly(vinyl formal), and gelatin. The preferred surface active agent is PVA of varying degrees of hydrolysis because of its low cost and good performance.
    Generally, the scale prevention composition is prepared by mixing a solution of the terpolymer, surface active agent, and the inorganic binder. If the scale prevention composition is to be applied to the surfaces of the reactor, a solvent is included, forming a solution of about 0.001 to about 20 wt% solids. Solutions of less solids are less effective and solutions of more solids inhibit the polymerization of the VCM. Preferably, the solution contains about 0.01 to about 5 wt% solids. Solvents that can be used to form the coating solution include, for example, water, alkaline water, and various organic solvents such as methylene chloride, tetrahydrofuran, dimethyl formamide, dimethylsulfoxide, and alcohols such as methanol and ethanol. The preferred solvent is a caustic solution of, for example, about 10 wt% or less sodium hydroxide, as it has been found to work well; other inorganic bases such as KOH, LiOH, and Ca(OH)2 are also expected io work well.
    The terpolymer can be applied to the reactor walls and to reactor components that are in contact with the VCM by any suitable means including, for example, spraying, flooding, painting, and brushing. After the application, it is not necessary to evaporate the solvent from the coating composition. Generally, the solids content of the coating on the reactor walls and components should be about 1 x 10-5 to about 1 x 10-3 g/square inch (about 1.6x10-6 to about 1.6x10-4 g/cm2) as less may not be effective and more is unnecessary.
    The terpolymer can also be added directly to the polymerization composition: For emulsion polymerizations, the polymerization composition typically consists of water, vinyl monomer, a free radical initiator, and an emulsifier. For suspension polymerizations, the polymerization composition typically consists of water, vinyl monomer, a free radical initiator, and a suspending agent. Generally, about 0.0001 to about 0.01 wt% of the terpolymer is added to the polymerization composition, based on the weight of the monomer. Less terpolymer is ineffective and more terpolymer may inhibit polymerization of the monomer.
    The terpolymer of this invention can also be used in gas phase or bulk polymerizations of vinyl monomers. But the present invention is particularly suitable for polymerizations in an aqueous medium, such as suspension or emulsion polymerization. The terpolymer can be used in both continuous and batch polymerizations.
    The following examples further illustrates this invention.
    Examples 1 to 21 - Preparation of Resins
    Into a 100 mL flask was placed the aromatic compound and the thiourea followed by the carbonyl compound. Unless otherwise stated, all reactions were carried out using 1.2 mL of 2M HCl/mmol of the carbonyl compound as the catalyst/solvent. The heterogeneous mixture was heated to reflux. After refluxing for a total of 5 hours, the reaction mixture was filtered and the solids were washed thoroughly with hot water. The wet filter cake was dissolved in 5 wt% aqueous sodium carbonate solution and acidified with 50% (v/v) HCl until the pH of the solution was about 1. A copious amount of solid resulted which was filtered, washed with water, and air dried. This procedure was used to prepare various terpolymer resins as described in Table 1.
    Ex # Aromatic compound (g) Carbonyl compound (g) Thiourea Derivative (g) Product Appearance;
    yield (g, %)
    1 Salicylic acid (6.91) Trioxane (9) Thiourea (3.81) Off-white solid;
    7.0, 59
    2 2'-Hydroxyacetophenone (8.06) Trioxane (10.66) Thiourea (4.51) Light yellow solid;
    9.5, 68
    3 2'-Hydroxyacetophenone (6.8) Trioxane (4.5) Thiourea (3.8) Yellow solid;
    3.8.27
    4 2'-Hydroxyacetophenone (6.8) Trioxane (4.5) Thiourea (7.6) Viscous yellow oil;
    5.2, 29
    5 2'-Hydroxyacetophenone (13.6) Trioxane (4.5) Thiourea (7.6) Yellow oil;
    2.0, 8
    6 2'-Hydroxyacetophenone (13.6) Trioxane (9) Thiourea (3.8) Orange oil;
    5.8, 23
    7 2'-Hydroxyacetophenone (13.6) Trioxane (4.5) Thiourea (7.6) Yellow-orange solid;
    0.98, <5
    8 2'-Hydroxyacetophenone (6.8) Trioxane (9) Thiourea (7.6) Yellow solid;
    6.7, 30
    9 O-Methylsalicylic acid (7.61) Trioxane (9) Thiourea (3.81) Colorless viscous oil;
    11.3, 57
    10 2-Hydroxy-1-naphthoic acid (9.4) Trioxane (9) Thiourea (3.81) White solid;
    10.3, 72
    11 4-Hydroxybenzenesulfonic acid (65 wt% aqueous solution, 13.4) Trioxane (9) Thiourea (3.81) White solid;
    12.57
    12 1-Naphthol (8.65) Trioxane (10.8) Thiourea (4.56) Brown solid:
    6.6, 27
    13 4-Hydroxybenzoic acid (6.91) Trioxane (9) Thiourea (3.81) Light tan solid;
    5.25
    14 Mercaptosalicylic acid (7.7) Trioxane (9) Thiourea (3.81) White solid;
    6.7, 33
    15 2'-Hydroxypropiophenone (7.5) Trioxane (9) Thiourea (3.81) Light yellow solid;
    6.2, 31
    16 2'-Hydroxypropiophenone (7.5) Trioxane (9) Thiourea (3.81) Yellow Solid;
    6.2, 31
    17 2',4'-Dhydroxypropiophenone (4.15) Trioxane (4.5) Thiourea (1.9) Light yellow powder;
    4.6, 44
    18 2,4'-Dihydroxyacetophenone (7.6) Trioxane (9) Thiourea (3.81) Light tan powder;
    13.46, 66
    19 2'-Hydroxypropiophenone (7.5) Trioxane (9) Thiosemicarbazide (4.56) Light brown resinous solid;
    9.54, 45
    20 1-Naphthol (7.5) 37 wt% Formaldehyde in water (39) Thiourea (3.95) Reddish brown solid;
    8.26 g
    21 1-Naphthol (9) 37 wt% Formaldehyde in water (47) Thiosemicarbazide (5.69) Light brown powder;
    16.7 g
    Example 22 (Comparative)
    A commercial sample of "EVICAS-90" coating solution supplied by European Vinyls Corporation was used as such in vinyl chloride polymerization.
    Example 23 (Comparative)
    A 1-naphthol/formaldehyde condensate was prepared as described in Example 1 of U.S. Patent 4,431,783. The product was a deep blue aqueous sodium hydroxide solution of the condensate.
    Polymerization of Vinyl Monomers
    The following methods were used to carry out vinyl chloride polymerization in the suspension mode in the presence of the various scale prevention agents of this invention. By a proper choice of emulsifying agent and reaction apparatus, one can also carry out vinyl chloride polymerization in the emulsion mode.
    Example 24 Suspension Polymerization of Vinyl Chloride, General Procedure.
    A rectangular SS-304 mill finish coupon, 12.5 inches (32 cm) long, 3 inches (8 cm) wide, and 0.015 inches (0.4 mm) thick (available from Metal Samples Inc., Munford, Alabama) was rolled into a cylinder of about 3 inches (7.6 cm) long and about 3.6 inches (9 cm) in diameter, such that it would fit snugly along the walls of a 1-liter Monel autoclave. A coating candidate was dissolved in 3 wt% aqueous NaOH solutions to prepare 2 wt% solutions of the scale prevention agents. These solutions were applied manually on both sides of the coupon with a brush and were allowed to dry overnight under ambient air.
    Into a 1-liter Monel autoclave was placed the SS-304 coupon coated with the scale prevention agent. The autoclave was sealed and subjected to three cycles of evacuation followed by nitrogen purge. After evacuating the autoclave again, a water solution of 0.66 g of hydroxypropyl cellulose, sold by Dow Chemical Co. as "Methocell E50" in 450 mL of deaerated demineralized water was sucked into the autoclave. The pressure inside the autoclave was brought to atmospheric by admitting nitrogen.
    Meanwhile, about 225 g (about 0.5 mole) of vinyl chloride was condensed from a VCM lecture bottle into a dry ice-cooled overhead VCM charging bomb. The VCM was charged into the autoclave under an overhead nitrogen pressure of 80 psi (553 kPa). Excess nitrogen pressure was carefully vented until the final equilibrium pressure of about 35 psi (241 kPa) at a temperature of about 16 to 18°C was attained. The initiator, 0.7 mL of 75 wt% tert-butylperoxyneodecanoate in odorless mineral spirits, sold as "Luperox 10M-75" by Elf Atochem N.A., was injected via a septum and the mixture was agitated at about 500 rpm. The reaction mixture was heated at a uniform rate over about 45 min. until the internal reactor temperature reached 62°C. After stirring for 5 hours, the heat was turned off, the excess vinyl chloride was vented off, and the PVC water slurry was filtered. The PVC obtained was air dried at room temperature to a constant weight. It was tested for lightness and yellowness (ASTM E1164 - standard practice for obtaining spectrophotometric data for object color evaluation). Table 2 gives the scale prevention agents tested and the results:
    Scale Prevention Agent (Example No.) PVC Yield (g) Lightness (L) Yellowness Index (YI) Comments
    23 187 93.57 7.07 No fouling on inner wall of coupon
    1 164 97.02 3.84 No fouling on inner wall. Better particle morphology than Ex 23
    11 197 97.47 1.31 No fouling on inner wall Better particle morphology than Ex 23
    14 182 96.74 1.61 No fouling on inner wall of coupon Better particle morphology than Ex 23
    None 185 96.92 2.19 Fouling on inner wall of coupon
    In Table 2, 100 is a perfect lightness score and 0 is a perfect yellowness score Table 2 shows that the terpolymers of this invention (Examples 1, 11, and 14) produced PVC comparable in yield and scale-prevention performance to the scale prevention agent of Example 23, but superior in lightness and yellowness characteristics.
    Example 25 Suspension Polymerization of Vinyl Chloride, General Procedure.
    A 500 mL EZE SS-316 autoclave equipped with a cooling jacket and a stirrer (from Autoclave Engineers) was coated completely on its inner surfaces with the coating solution prepared above. The autoclave was sealed and subjected to three cycles of evacuation followed by nitrogen purge. After evacuating the autoclave again, a water solution of 0.1 g of "Methocell E50" in 190 mL of deaerated demineralized water was sucked into the autoclave. Then 18 mL of a 1% poly(vinyl alcohol) (80% hydrolyzed; Aldrich) in degassed, demineralized water was introduced via a septum into the autoclave. The autoclave was then evacuated again briefly without being stirred and cooled to about 5°C. Vinyl chloride gas was condensed into the autoclave with stirring until ¼ lb (113 g) of monomer had been transferred. When the internal pressure was below 20 psig, the polymerization initiator (0.15 mL of 75 wt% "Luperox 10M-75") was syringed out and injected into the autoclave via a septum, and the mixture was agitated at 500 rpm. The coolant fluid circulation to the reactor jacket was stopped and another circulating bath pre-heated to about 72°C was connected to the reactor jacket. The reactor temperature was set to 62°C on the control tower. The internal reactor temperature reached 62°C in about 0.5 h. After being stirred for 5 hours, heating was turned off, the excess vinyl chloride was vented off, and the PVC water slurry was filtered. The PVC obtained was then air dried at room temperature to a constant weight. It was tested for lightness and yellowness (ASTM E1164). Results obtained in evaluation of several novel coating candidates are shown in Table 3. To determine PVC resin color only one coating candidate was coated on the reactor wall. The color results are shown in Table 4. In Table 4, 100 is a perfect lightness score and 0 is a perfect yellowness score. The table shows that terpolymers used in this invention produced PVC comparable in yield and scale-prevention performance to the commercial scale prevention agent (Example 41), but superior in lightness (L) and yellowness characteristics (lower "b" value).
    Example 26
    Vinyl chloride polymerization was carried out using the general procedure outlined in Example 25, but no scale prevention agent was used.
    Examples 27 to 41
    Vinyl chloride polymerizations were carried out according to the general procedure outlined in Example 25 and many of the scale prevention agents described in the Examples. In some experiments, two or more coatings were applied on different sections of the reactor wall.
    Example 42 (Comparative)
    Vinyl chloride polymerization was carried out using the general procedure outlined in Example 25 and the scale prevention agent described in Example 22.
    . Tables 3 and 4 give the results of the vinyl chloride polymerizations of Examples 26 to 42. All reactor coatings were formulated in an 80/20 misture of 2 wt% aqueous NaOH/ethanol unless otherwise indicated.
    Polymerization Example Coating Example(s) Fouling Observations
    Solution Interfacial
    26 No Coating High High
    27 2 Medium High
    11 Medium High
    28 3 Low Medium
    4 Low Medium
    2 Low Medium
    5 Low Medium
    29 6 Low Medium
    7 Low Medium
    8 Low Medium
    2 Low High
    30 9 Medium Medium
    31 15 None None
    15 None Very Low
    32 15 Low None
    15 Very Low None
    33 15 None None
    34 15 Medium Low
    Figure 00250001
    Figure 00260001
    Tables 3 and 4 show that the terpolymers of this invention are as effective as commercial products in preventing scale and in yield, but produce PVC that is lighter and less yellow.
    In the present specification the word "comprise" or "comprises" means "includes or consists of" and "comprising" means "including or consisting of".

    Claims (19)

    1. A method of inhibiting the formation of scale on a reactor surface in contact with a polymerizing vinyl monomer comprising contacting said monomer with a terpolymer which comprises the condensation reaction product of
      (A) an aromatic compound that contains the group
      Figure 00270001
      where Q is OR or SR and R is hydrogen, alkyl from C1 to C15, or aryl, alkaryl, or aralkyl from C6 to C15;
      (B) 0.1 to 10 moles of a carbonyl compound per mole of said aromatic compound; and
      (C) 0.1 to 10 moles of a thiourea per mole of said aromatic compound.
    2. A method according to Claim 1 wherein a solution of said terpolymer is prepared in a solvent and said solution is applied to a reactor surface that is exposed to said monomer.
    3. A method according to Claim 2 wherein said solvent is water containing NaOH, KOH, LiOH, or Ca(OH)2.
    4. A method according to Claim 1 or Claim 2 wherein said monomer is polymerized in an aqueous suspension or an aqueous emulsion and said terpolymer is added to said aqueous suspension or said aqueous emulsion.
    5. A method according to any one of the preceding Claims wherein said aromatic compound is selected from the group consisting of
      Figure 00280001
      Figure 00280002
      where Z is O or NOH, each R1 is independently selected from OH, R, SO3R, and CO2R, and each R2 is independently selected from R1, SH, SR, haloalkyl from C1 to C15, alkoxyaryl, naphthyl, and polycyclic aryl from C6 to C15.
    6. A method according to any one of the preceding Claims wherein said carbonyl compound is selected from the group consisting of compounds having the general formula
      Figure 00290001
      where each R2 is independently selected from R1, SH, SR, haloalkyl from C1 to C15, alkoxyaryl, naphthyl, and polycyclic aryl from C6 to C15, R1 is OH, R, SO3R, or CO2R, and n is an integer from 1 to 10.
    7. A method according to any one of the preceding Claims wherein said thiourea has the general formula
      Figure 00290002
      where each R2 is independently selected from R1, SH, SR, NH2, haloalkyl from C1 to C15, alkoxyaryl, naphthyl, and polycyclic aryl from C6 to C15, and R1 is OH, R, SO3R, or CO2R.
    8. A vinyl polymerization composition containing 0.0001 to 0.01 wt% of a terpolymer according to any one of the preceding Claims.
    9. A vinyl polymerization reactor having a coating containing a terpolymer according to any one of Claims 1 to 8 on an inside surface.
    10. A method according to Claim 1 wherein the terpolymer is present as a solution in a solvent of 0.001 to 20 wt% of the terpolymer and wherein said aromatic compound is selected from the group consisting of compounds having the general formula
      Figure 00300001
      Figure 00300002
      and wherein there is 0.1 to 5 moles of said carbonyl compound per mole of said aromatic compound, the carbonyl compound being selected from the group consisting of compounds having the general formula
      Figure 00300003
      where n is an integer from 1 to 10; and wherein there is 0.1 to 5 moles of said thiourea per mole of said aromatic compound, the thiourea having the general formula
      Figure 00310001
      where Z is O or NOH, each R1 is independently selected from OH, R, SO3R, and CO2R, each R2 is independently selected from R1, SH, SR, NH2, haloalkyl from C1 to C15, alkoxyaryl, naphthyl, and polycyclic aryl from C6 to C15, and R is hydrogen, alkyl from C1 to C15, or aryl, alkaryl, or aralkyl from C6 to C15.
    11. A method according to Claim 10 wherein said solvent is water.
    12. A method according to Claim 1 wherein the terpolymer is 0.0001 to 0.01 wt% of the monomer and wherein said aromatic compound is selected from the group consisting of compounds having the general formula
      Figure 00320001
      Figure 00320002
      and wherein there is 0.1 to 5 moles of said carbonyl compound per mole of said aromatic compound, the carbonyl compound being selected from compounds having the general formula
      Figure 00320003
      where n is an integer from 1 to 10; and wherein there is 0.1 to 5 moles of thiourea having the general formula
      Figure 00330001
      where Z is O or NOH, each R1 is independently selected from OH, R, SO3R, and CO2R, each R2 is independently selected from R1, SH, SR, NH2, haloalkyl from C1 to C15, alkoxyaryl, naphthyl, and polycyclic aryl from C6 to C15, and R is hydrogen, alkyl from C1 to C15, or aryl, alkaryl, or aralkyl from C6 to C15.
    13. A method according to Claim 12 wherein said solvent is an aqueous sodium hydroxide.
    14. A method according to any one of the preceding claims wherein said aromatic compound is 2'-hydroxypropiophenone or 1-naphthol.
    15. A method according to any one of the preceding claims wherein said carbonyl compound is formaldehyde or an oligomer thereof.
    16. A method according to any one of the preceding claims wherein said thiourea is thiourea or thiosemicarbazide.
    17. A terpolymer comprising the reaction product of
      (A) an aromatic compound that contains a benzene ring substituted with the group OR, SH or SR, or a naphthalene ring substituted with the group OR, OH, SH or SR; where R is alkyl from C1 to C15, or aryl, alkaryl, or aralkyl from C6 to C15,
      (B) 0.1 to 10 moles of a carbonyl compound per mole of said aromatic compound; and
      (C) 0.1 to 10 moles of thiosemicarbazide per mole of said aromatic compound.
    18. A terpolymer according to Claim 17 wherein said aromatic compound is 2'-hydroxypropiophenone and said carbonyl compound is trioxane.
    19. A terpolymer according to Claim 17 wherein said aromatic compound is 1-naphthol and said carbonyl compound is formaldehyde.
    EP99936832A 1998-08-10 1999-07-30 Inhibiting scale in vinyl monomer polymerization Expired - Lifetime EP1098912B1 (en)

    Applications Claiming Priority (3)

    Application Number Priority Date Filing Date Title
    US131347 1998-08-10
    US09/131,347 US6114476A (en) 1998-08-10 1998-08-10 Inhibiting scale in vinyl monomer polymerization
    PCT/GB1999/002513 WO2000009570A1 (en) 1998-08-10 1999-07-30 Inhibiting scale in vinyl monomer polymerization

    Publications (2)

    Publication Number Publication Date
    EP1098912A1 EP1098912A1 (en) 2001-05-16
    EP1098912B1 true EP1098912B1 (en) 2004-03-10

    Family

    ID=22449047

    Family Applications (1)

    Application Number Title Priority Date Filing Date
    EP99936832A Expired - Lifetime EP1098912B1 (en) 1998-08-10 1999-07-30 Inhibiting scale in vinyl monomer polymerization

    Country Status (12)

    Country Link
    US (2) US6114476A (en)
    EP (1) EP1098912B1 (en)
    JP (1) JP4253129B2 (en)
    AT (1) ATE261455T1 (en)
    CA (1) CA2339975A1 (en)
    DE (1) DE69915484T2 (en)
    DK (1) DK1098912T3 (en)
    ES (1) ES2217786T3 (en)
    HK (1) HK1034720A1 (en)
    PT (1) PT1098912E (en)
    TW (1) TWI223653B (en)
    WO (1) WO2000009570A1 (en)

    Families Citing this family (5)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    US7500917B2 (en) * 2000-02-22 2009-03-10 Creative Kingdoms, Llc Magical wand and interactive play experience
    MXPA04009883A (en) * 2002-04-11 2004-12-07 Akzo Nobel Nv Method for the application of anti-fouling agents.
    US8945610B2 (en) * 2007-11-14 2015-02-03 Basf Se Condensation products based on bicyclic or polycyclic aromatics or heteroaromatics
    EP2581421A1 (en) 2011-10-12 2013-04-17 Ineos Europe AG Additive
    JP7427835B1 (en) 2023-07-07 2024-02-05 信越化学工業株式会社 Composition, method for producing the composition, anti-scaling agent, reaction device, polymer, method for producing the polymer

    Family Cites Families (19)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    US3969244A (en) * 1970-06-09 1976-07-13 Hokuetsu Carbon Industry Co., Ltd Method of adsorbing heavy metals
    JPS49461A (en) * 1972-04-19 1974-01-05
    JPS5150989A (en) * 1974-10-31 1976-05-06 Shinetsu Chemical Co Enkabiniru mataha enkabiniruoshutaitosuru tanryotaikongobutsuno jugohoho
    CS185932B1 (en) * 1976-04-23 1978-10-31 Jaroslav Cerny Process for preparing thermoreactive phenolaminoformaldehyde resins
    JPS5322600A (en) * 1976-08-13 1978-03-02 Miyoshi Yushi Kk Chelate resin for adsorbing heavy metals and process for producing said resin
    JPS53113889A (en) * 1977-03-15 1978-10-04 Unitika Ltd Phenol-type chaelate resin, its preparation and adsorption treatment
    JPS5614506A (en) * 1979-07-17 1981-02-12 Tokuyama Sekisui Kogyo Kk Suspension polymerization of vinyl chloride
    JPS578207A (en) * 1980-06-17 1982-01-16 Tokuyama Sekisui Kogyo Kk Suspension polymerization of vinyl chloride
    ATE23866T1 (en) * 1980-10-31 1986-12-15 Ici Plc VINYL CHLORIDE POLYMERIZATION PROCESS.
    JPS59202201A (en) * 1983-04-28 1984-11-16 Shin Etsu Chem Co Ltd Polymer scale deposition preventing agent and its use
    FI832553A (en) * 1983-07-19 1985-01-14 Gosudarstvenny Nauchno- Issledovatelsky I Proektny Institut/Po Obogascheniju Rud Tsvetnykh Metallov Çkazmekhanobrç POLYMER MATERIAL FOR PHYSICAL AND CHEMICAL PROCESSING OF OIL FOR FARING FRAMSTATION OF MATERIALS.
    FR2631966B1 (en) * 1988-05-24 1992-03-13 Solvay
    JP3190055B2 (en) * 1991-03-19 2001-07-16 三井化学株式会社 Novel phenolic co-condensation resin with improved water solubility and its production method
    TW289759B (en) * 1992-03-16 1996-11-01 Shinetsu Chem Ind Co
    JP2678715B2 (en) * 1992-11-10 1997-11-17 信越化学工業株式会社 Polymer scale adhesion inhibitor and method for producing polymer using the same
    US5484855A (en) * 1993-01-13 1996-01-16 Shin-Etsu Chemical Co., Ltd. Polymer scale preventive process
    CA2128572A1 (en) * 1993-07-22 1995-01-23 Toshihide Shimizu Polymer scale deposition preventive agent
    JP3317803B2 (en) * 1994-11-15 2002-08-26 信越化学工業株式会社 Polymer scale adhesion inhibitor and method for producing polymer using the same
    US6001937A (en) * 1998-11-17 1999-12-14 Occidental Chemical Corporation Reducing scale in vinyl polymerizations

    Also Published As

    Publication number Publication date
    US6114476A (en) 2000-09-05
    HK1034720A1 (en) 2001-11-02
    TWI223653B (en) 2004-11-11
    DE69915484D1 (en) 2004-04-15
    PT1098912E (en) 2004-05-31
    WO2000009570A1 (en) 2000-02-24
    ATE261455T1 (en) 2004-03-15
    US6300427B1 (en) 2001-10-09
    EP1098912A1 (en) 2001-05-16
    DE69915484T2 (en) 2004-08-05
    DK1098912T3 (en) 2004-06-07
    ES2217786T3 (en) 2004-11-01
    CA2339975A1 (en) 2000-02-24
    JP4253129B2 (en) 2009-04-08
    JP2002522600A (en) 2002-07-23

    Similar Documents

    Publication Publication Date Title
    EP0372996B1 (en) Method of preventing polymer scale deposition in a polymerization vessel
    CA2825575A1 (en) A process for producing polycondensation product
    EP1098912B1 (en) Inhibiting scale in vinyl monomer polymerization
    HU216429B (en) Polymer scale preventive composition and process for producing a polymer
    US6506854B2 (en) Inhibiting scale in vinyl monomer polymerization
    US5416174A (en) Scale preventive coating of pyrogallol-acetone resin and water soluble polymer
    EP0372968B1 (en) Method of preventing polymer scale formation
    US6001937A (en) Reducing scale in vinyl polymerizations
    WO1991009879A1 (en) Polymerization of vinyl chloride
    ITMI962548A1 (en) ANTI-SCALING AGENTS, COMPOSITIONS THAT CONTAIN THEM AND THEIR USE IN THE POLYMERIZATION PROCESSES
    EP0473837B1 (en) Method of preventing polymer scale deposition and polymer scale preventive agent
    CA2043278A1 (en) Method of preventing polymer scale deposition and polymer scale preventive liquid used therein
    KR0167003B1 (en) Scale suppressant vinyl chloride homo and copolymerization method
    US4940759A (en) Process for making film grade PVC
    US4980079A (en) Agent for preventing vinyl chloride polymer build-up
    US4588613A (en) Process for reducing polymer buildup
    US5574115A (en) Process for polymerization with suppressed polymer scale formation
    EP0475186B1 (en) Polymer scale preventive agent, and polymerization vessel and method for preventing polymer scale deposition
    EP0382102B1 (en) Method of preventing polymer scale deposition
    US5442017A (en) Process for producing polymer wherein polymer scale deposition is prevented
    JP2003192754A (en) Manufacturing process for scaling-preventive agent
    US5214113A (en) Method of preventing polymer scale deposition and polymer scale preventive agent
    CA1335746C (en) Process for making film grade pvc
    JPH06166703A (en) Agent for preventing adhesion of polymer scale, polymerizer for preventing adhesion of polymer scale and production of polymer using the same
    JPH05194607A (en) Agent for preventing deposition of polymer scale, polymerizer effective for preventing deposition of polymer scale and production of polymer using the polymerizer

    Legal Events

    Date Code Title Description
    PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

    Free format text: ORIGINAL CODE: 0009012

    17P Request for examination filed

    Effective date: 20010309

    AK Designated contracting states

    Kind code of ref document: A1

    Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

    RIN1 Information on inventor provided before grant (corrected)

    Inventor name: HICHRI, HIBIB

    Inventor name: WANG, QI

    Inventor name: NAGY, SANDOR, M.

    Inventor name: KRISHNAMURTI, RAMESH

    RIN1 Information on inventor provided before grant (corrected)

    Inventor name: HICHRI, HIBIB

    Inventor name: WANG, QI

    Inventor name: NAGY, SANDOR, M.

    Inventor name: KRISHNAMURTI, RAMESH

    REG Reference to a national code

    Ref country code: GB

    Ref legal event code: FG4D

    GRAP Despatch of communication of intention to grant a patent

    Free format text: ORIGINAL CODE: EPIDOSNIGR1

    GRAS Grant fee paid

    Free format text: ORIGINAL CODE: EPIDOSNIGR3

    GRAA (expected) grant

    Free format text: ORIGINAL CODE: 0009210

    AK Designated contracting states

    Kind code of ref document: B1

    Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: LI

    Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

    Effective date: 20040310

    Ref country code: FI

    Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

    Effective date: 20040310

    Ref country code: CY

    Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

    Effective date: 20040310

    Ref country code: CH

    Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

    Effective date: 20040310

    Ref country code: AT

    Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

    Effective date: 20040310

    REG Reference to a national code

    Ref country code: CH

    Ref legal event code: EP

    REG Reference to a national code

    Ref country code: IE

    Ref legal event code: FG4D

    REF Corresponds to:

    Ref document number: 69915484

    Country of ref document: DE

    Date of ref document: 20040415

    Kind code of ref document: P

    REG Reference to a national code

    Ref country code: PT

    Ref legal event code: SC4A

    Free format text: AVAILABILITY OF NATIONAL TRANSLATION

    Effective date: 20040330

    REG Reference to a national code

    Ref country code: DK

    Ref legal event code: T3

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: SE

    Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

    Effective date: 20040610

    Ref country code: GR

    Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

    Effective date: 20040610

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: LU

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20040730

    Ref country code: IE

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20040730

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: MC

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20040731

    REG Reference to a national code

    Ref country code: CH

    Ref legal event code: PL

    REG Reference to a national code

    Ref country code: ES

    Ref legal event code: FG2A

    Ref document number: 2217786

    Country of ref document: ES

    Kind code of ref document: T3

    ET Fr: translation filed
    REG Reference to a national code

    Ref country code: HK

    Ref legal event code: GR

    Ref document number: 1034720

    Country of ref document: HK

    PLBE No opposition filed within time limit

    Free format text: ORIGINAL CODE: 0009261

    STAA Information on the status of an ep patent application or granted ep patent

    Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

    26N No opposition filed

    Effective date: 20041213

    REG Reference to a national code

    Ref country code: IE

    Ref legal event code: MM4A

    PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

    Ref country code: DK

    Payment date: 20080617

    Year of fee payment: 10

    PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

    Ref country code: PT

    Payment date: 20080627

    Year of fee payment: 10

    PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

    Ref country code: ES

    Payment date: 20080704

    Year of fee payment: 10

    Ref country code: DE

    Payment date: 20080731

    Year of fee payment: 10

    PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

    Ref country code: NL

    Payment date: 20080619

    Year of fee payment: 10

    Ref country code: IT

    Payment date: 20080723

    Year of fee payment: 10

    Ref country code: FR

    Payment date: 20080707

    Year of fee payment: 10

    PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

    Ref country code: GB

    Payment date: 20080616

    Year of fee payment: 10

    PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

    Ref country code: BE

    Payment date: 20080730

    Year of fee payment: 10

    BERE Be: lapsed

    Owner name: *OXY VINYLS L.P.

    Effective date: 20090731

    REG Reference to a national code

    Ref country code: PT

    Ref legal event code: MM4A

    Free format text: LAPSE DUE TO NON-PAYMENT OF FEES

    Effective date: 20100201

    REG Reference to a national code

    Ref country code: DK

    Ref legal event code: EBP

    GBPC Gb: european patent ceased through non-payment of renewal fee

    Effective date: 20090730

    NLV4 Nl: lapsed or anulled due to non-payment of the annual fee

    Effective date: 20100201

    REG Reference to a national code

    Ref country code: FR

    Ref legal event code: ST

    Effective date: 20100331

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: PT

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20100201

    Ref country code: FR

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20090731

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: GB

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20090730

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: DE

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20100202

    Ref country code: BE

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20090731

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: DK

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20090731

    REG Reference to a national code

    Ref country code: ES

    Ref legal event code: FD2A

    Effective date: 20090731

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: ES

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20090731

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: IT

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20090730

    PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

    Ref country code: NL

    Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

    Effective date: 20100201